The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Referring now to FIG. 1, a functional block diagram of an internal combustion engine 100 (hereinafter engine 100) is shown. A control module 104 controls the operation of the engine 100. The control module 104 may also control a transmission 108. The control module 104 may receive driver input from an accelerator input module 110 and from a transmission input module 112. The driver input may indicate an amount of torque requested or demanded.
The accelerator input module 110 may include an accelerator pedal and pedal position sensors (both not shown). The pedal position sensors may sense a rate of change of the accelerator pedal. The accelerator input module 110 may determine the amount of torque requested or demanded based on the rate of change of the accelerator pedal. The transmission input module 112 may include a gearshift lever, gearshift paddles, and/or gearshift buttons (all not shown).
Based on the driver input, the control module 104 controls a throttle valve 116. The throttle valve 116 regulates air intake into an intake manifold 118 of the engine 100. The position of the throttle valve 116 may be measured by a throttle position sensor 120. The amount of air flowing into the intake manifold 118 may be measured by a mass air flow (MAF) sensor 122. The pressure inside the intake manifold 118 may be measured by a manifold absolute pressure (MAP) sensor 124. Air from the intake manifold 118 is combined with fuel to create an air-fuel mixture in one or more cylinders 126. Eight cylinders 126-1, 126-2, . . . , and 126-8 (collectively cylinders 126) are shown for example only. The engine 100 may comprise additional or fewer cylinders.
Combusting the air-fuel mixture in the cylinders 126 produces torque that turns a crankshaft (not shown). The crankshaft is coupled to the transmission 108 via a torque transmitting device 130. The torque transmitting device 130 may include a torque converter or a clutch. A revolutions-per-minute (RPM) sensor 132 may measure the speed of the crankshaft. The speed of the crankshaft represents the speed of the engine 100 (i.e., an engine speed).
Depending on the torque demand indicated by the driver input, the control module 104 may deactivate and reactivate one or more of the cylinders 126. When maximum torque is not required, the control module 104 may deactivate one or more of the cylinders 126 to improve fuel economy. For example, the cylinders 126 shown shaded (e.g., cylinders 126-1, etc.; hereinafter selected cylinders) may be deactivated. Subsequently, when the driver input indicates that an additional torque is demanded, the control module 104 reactivates the selected cylinders.
The control module 104 may deactivate and reactivate the selected cylinders in different ways. For example only, the control module 104 may operate a lifter oil manifold assembly (LOMA) 134 comprising solenoid-actuated oil control valves (OCVs) (not shown) that deactivate and reactivate the selected cylinders in response to the control module 104.
Each of the cylinders 126 receives air through an intake valve and outputs exhaust gases generated by combustion through an exhaust valve (both not shown). The intake and exhaust valves of the cylinders 126 may be actuated by rocker arms via pushrods driven off a camshaft (all not shown). The pushrods may include hydraulically-controlled switchable lost motion devices (SLMDs) (not shown).
To deactivate the selected cylinders, the OCVs send hydraulic signals to the SLMDs corresponding to the selected cylinders. Actuating the SLMDs decouples the rocker arms from the camshaft and closes the intake and exhaust valves of the selected cylinders. When the intake and exhaust valves of the selected cylinders are closed, the selected cylinders are deactivated. Subsequently, based on the torque demand, the OCVs may reactivate the selected cylinders by enabling the corresponding SLMDs and reopening the intake and exhaust valves of the selected cylinders.